In many processes it is desired that a particular product be introduced to a chemical bath or spray. Such chemical process may include painting or cleaning or the process may consist of pickling metal products. For example, in the production of galvanized wire it is advantageous to clean and pickle the bare steel wire with hydrochloric acid before finally galvanizing the wire in a zinc bath.
There are several problems associated with cleaning and pickling (hereinafter refered to simply as pickling). One problem common to pickling processes is the generation of harmful, corrosive fumes. In pickling of metal such as wire, the wire is typically dipped through a bath of hydrochloric acid. Fumes from the bath are a health hazard and tend to corrode nearby equipment when the fumes condense thereon. One solution to this problem is to provide a high capacity ventilation system which proposes to draw the fumes into a hood and dispose of them by suitable means. Such ventilation systems are not entirely satisfactory in that a portion of the fumes still tend to escape and such ventilation systems are expensive. Where federal, state or local ordinance dictate certain clean air standards, such systems can become even more expensive.
Another solution to the problem of fumes is to provide a closed top for the tank. For batch pickling, the fumes still tend to escape when the tank is opened to remove the batch. For continuous pickling of, for example, long strands of wire, the fumes tend to escape from the open ends of the tank through which the wire is continuously passed. Furthermore, the tank must be opened to load the wire strands into the tank, again permitting the hazardous, corrosive fumes to escape.
As can be appreciated, there is a need for a device and method by which a product can be treated, either on a continuous throughput or on a batch basis, which prevents the escape of fumes and does not require expensive ventilation and exhaust systems.